Differences in Virulence among PVY Isolates of Different Geographical Origins When Infecting an Experimental Host under Two Growing Environments Are Not Determined by HCPro.

The contribution of the HCPro factors expressed by several PVY isolates of different geographical origins (one from Scotland, one from Spain, and several from Tunisia) to differences in their virulence in plants was investigated under two growing conditions: standard (st; 26 °C and current ambient levels of CO), and climate change-associated (cc; 31 °C and elevated levels of CO). In all cases, relative infection symptoms and viral titers were determined. The viral cistrons were also sequenced and amino-acid features of the encoded proteins were established, as well as phylogenetic distances.

Topical Application of -Encapsulated dsRNA Induces Resistance in to Potato Viruses and Involves RDR6 and Combined Activities of DCL2 and DCL4.

Exogenous application of double-stranded RNAs (dsRNAs) for inducing virus resistance in plants represents an attractive alternative to transgene-based silencing approaches. However, improvement of dsRNA stability in natural conditions is required in order to provide long-term protection against the targeted virus. Here, we tested the protective effect of topical application of -encapsulated dsRNA compared to naked dsRNA against single and dual infection by expressing the green fluorescent protein (PVX-GFP) and Potato virus Y (PVY) in .

Biological, serological and molecular typing of potato virus Y (PVY) isolates from Tunisia.

In Tunisia, potato virus Y (PVY) currently presents a significant threat to potato production, reducing tuber yield and quality. Three hundred and eighty-five potato samples (six different cultivars) collected in autumn 2007 from nine regions in Tunisia were tested for PVY infection by DAS-ELISA. The virus was detected in all regions surveyed, with an average incidence of 80.

Nucleotide sequence analysis of the ORF0 region of Potato leafroll virus isolates from Tunisia.

Potato leafroll virus (PLRV) isolates from potato plants from different regions of Tunisia were investigated for the ORF0 variable region of genomic RNA using PCR, nucleotide sequencing and sequence analysis. Based on the ORF0 variable region nucleotide sequence, individual Tunisian isolates were more homologous as a group compared to the isolates originating from other parts of the world. There was no correlation between bioclimatic origin of the isolates and their ORF0 sequence.